Scan the unavoidable lists of things successful entrepreneurs have in common and you’ll soon see the importance of books. Pretty much every entrepreneur who has ever reached an enviable level of success will cite reading as an essential daily habit.

Related: 9 Books Elon Musk Thinks Everyone Should Read

Of course we assume that they read books on business, and probably they do. I know my own bookshelves are overflowing with business classics and hidden gems on management, mindset and innovation.

But business isn't the only genre spilling off those shelves and piling up on my night table. I can argue that I’ve gleaned just as much business wisdom from nonbusiness books, whose reading list falls into five categories:

1. Books that challenge the way I see life

Right now Supersurvivors: The Surprising Link Between Suffering and Success is the one taking up space on my reading table and in my head. In it, authors David Feldman and Lee Daniel Kravetz examine how some people not only bounce back from severe trauma, but actually use that experience as a springboard to “jump forward.”

These true stories pretty much rip apart our notions about positive thinking, emotional support and the setting of goals and expectations. One idea in particular that has rearranged my thinking about interpersonal dynamics and social structure in business or any other aspect of life is Feldman and Kravetz's explanation for why people choose to blame the victims in any misfortune. That understanding alone has been worth every cent and second I’ve spent on this book.

2. Books that expand the way I use language

We depend on words for pretty much everything in business and in life. As a writer, I consider words my stock in trade, but all entrepreneurs depend on words to get what they want.

My reading (and rereading) list in this category would fill an average-sized bookcase, but two that I return to often for inspiration are Aspire: Discovering Your Purpose Through the Power of Words which, although written by business consultant Kevin Hall, with a forward by Stephen R. Covey, is not a book about business; and Writing Down the Bones: Freeing the Writer Within, by Natalie Goldberg, now in its second edition. Both of these books, in different ways, pull me back to a pattern of eloquence, honesty and articulateness that I can ill afford to forget.

Related: 50 Global Entrepreneurs Recommend 50 Books That Forever Impacted Their Lives

3. Books that help me understand my mind

I’m not sure that “great minds think alike,” but I am convinced that the more we understand about what the mind really is and how it works, the more success we will have in life and business. If you want to give yourself a headache trying to understand the mind, tackle The Mysterious Flame: Conscious Minds in a Material World, by Colin McGinn. More than any other of the 100 or so books I’ve read about the function of the mind, this one just keeps challenging me to rethink my thinking.

Another favorite, since many entrepreneurs have been through trauma and abuse and are also, like me, dependent on their creativity to continue to build wealth and fulfillment through their business, is The Mozart Effect: Tapping the Power of Music to Heal the Body, Strengthen the Mind, and Unlock the Creative Spirit, by Don Campbell. After reading the science and the stories, you’ll never experience music the same way again.

4. Books that make me go “hmm”

F. Scott Fitzgerald wrote that, "The test of a first-rate intelligence is the ability to hold two opposing ideas in mind at the same time and still retain the ability to function." If that is true, my Facebook time line is a pretty good test of my intelligence. But the title in this category that has spent considerable time on my list of books to study is The Universe in a Single Atom: The Convergence of Science and Spirituality by His Holiness the Dalai Lama.

Insightful and inspiring, this examination of the balance between spiritual beliefs and proven scientific principles has tested my intelligence and forced me to view my relationships and my business in a new light.

5. Books that make me laugh

More than any other source, stories teach us lessons we will never forget. The story doesn’t have to be true; in fact, it’s often the outlandish farce or fantasy that offers up truisms which inform our business and life decisions in little ways we may not even recognize.

Somewhere in Frank Herbert’s Dune I learned that “the path of least resistance always goes downhill.” If that isn’t a business lesson worth remembering, I don’t know what is. And then there’s the “ Somebody Else’s Problem field,” which sure explained a lot of the problems I encountered in corporate management.

I’m sure you have your own favorites in each of these categories. What have you learned about business from nonbusiness books?

Related: 11 Vital Books for First-Time Entrepreneurs